Device for fixing a fuel injector on an internal combustion engine cylinder head

ABSTRACT

The invention concerns a device for fixing a fuel injector on an internal combustion engine cylinder head consisting of a part called bottom part (2a) for covering at least an engine cylinder and a part called top part (2b) defining with the other part a chamber (5) containing mechanical members for actuating valves. The injector (1) passes through these two parts and is supported on the base (8) of a well (4) of the bottom part (2a) by a flange (9) fixed to the cylinder head (13) with screws, and by means of a tubular piece (10) enclosing the injector body and resting on the projecting part of a lock ring (16) mounted in a peripheral groove (15) of the injector body. The invention is characterized in that, the flange (9) is rigidly integral with the tubular piece (10) fitted in a cylindrical recess (14) of the top part (2b).

This invention is about a device to affix a fuel injector on thecylinder head of an internal combustion engine.

More particularly, the invention describes a device for an injector thatgoes through, nearly vertically, the cylinder head and exits it on aninterior surface that covers the supposedly vertical cylinder of theengine, and exits it on an accessible exterior surface.

In an implementation known in patent DE43 15 233, the affixing device isintegrated in the cylinder head, in a chamber that contains themechanical elements that actuate the valves, and contains a cylindricalsleeve that surrounds the body of the injector.

This latter possesses, along its central section located in the chamber,a peripheral groove able to receive a trim on which the sleeve comes torest on the bottom with the aid of an interior shoulder to immobilizethe injector against the lower bottom of a housing designed in thecylinder head, generally called injector well.

The sleeve extends toward the bottom from the shoulder forming a recessthat comes to tighten a protruding section of the cylinder head withinterposition of circular seal inserted in order to protect the body ofthe injector from the oil cloud in the chamber. Between the top sectionof the sleeve and a cover of the cylinder head delimiting the chamber isset a lipped gasket to insure the seal between the chamber and theoutside of the cylinder head.

The sleeve is attached in the cylinder head by a fork that rests on twoexterior transversal wings of the sleeve under the pressure of athreaded part screwed in the cylinder head.

Such a device congests the chamber by reducing the space available forthe valves and requires relatively costly seals; furthermore, thedisassembly of the fuel injector is difficult and a precarious balanceabove its attachment is detrimental to its reliability.

It is this invention's aim to show a device of the type described belowthat remedies the problems mentioned above.

In effect, the invention is about a device for affixing a fuel injectorto an internal combustion engine cylinder head that consists of a bottompart designed to cover an engine cylinder and a top part, which defineswith the other part a chamber that contains mechanical valve actuators.The injector passes through these two parts and is supported at the baseof a well of the bottom part by a flange attached to the cylinder headwith screws, and by means of a tubular piece that enclosed the body ofthe injector and rests on the protruding section of a trim ring mountedin a peripheral groove in the injector body, characterized in that theflange is rigidly integrated with the tubular piece, made of a sleeve,which is inserted in a cylindrical hollow of the top part.

According to a few interesting designs of the invention:

The sleeve is designed with a bore in which the body of the injector isinserted and of a peripheral groove in which is mounted a sealinggasket.

The trim is made of a split ring with complementarily shaped extremitiesdesigned to seal the body of the injector to the bore of the sleeve whensaid sleeve comes to rest against the trim under the pressure of theflange that is attached to the head gasket.

The sleeve contains, on it lower section, a circular base with bevelededges designed to insure the contact of the trim's extremities.

The characteristics of the invention mentioned above, as well as others,will appear more clearly during the reading of the following descriptionof an implementation example, referring to the drawings in the appendixon which:

FIG. 1 is a partial, longitudinal cut view of the invention's device toaffix a fuel injector on the head cylinder of an internal combustionengine;

FIG. 2 is a partial cut view that follows line II--II in FIG. 1;

FIG. 3 is a perspective view of the injector and of a part of theaffixing device;

FIG. 4 shows a perspective view of a flange of the device;

FIG. 5 is a top view of a trim of the device;

FIG. 6 is a cut view, to a greater scale, following line VI--VI of FIG.4

We can see, on FIGS. 1 and 2, a fuel injector 1 passing through a headcylinder 2 of a internal combustion engine and maintained on it by anattachment device D.

The head cylinder 2 contains on one hand a section called the bottompart 2a that is designed to cover at least one engine cylinder, heresupposed vertical, and on the other hand a section called top part 2bforming a cylinder head cover and a superior half-landing for at leastone crankshaft, not shown, interposed between the two parts 2aand 2b,that delimit between themselves a chamber 5 that contains valve commandmechanisms.

The injector 1 is made of a generally cylindrical body of which lowersection 3 is lodged in a hollow 4 called a well that is set in thebottom section 2a of the cylinder head and exits this section intochamber 5.

This latter is filled, during engine operation, of a cloud mist of oilthat lubricates moving parts.

The body of the injector 1 possesses in its lower section a radialshoulder 6 that rests, in the classic way, against the bottom 8 of thewell 4. A copper washer 7 is used between these elements as a seal.

According to this invention, the injector 1 is attached to the topsection 2b of the cylinder head with the aid of a attachment flange 9that is made of a cylindrical sleeve 10 that has a bore 10a.

The sleeve 10 contains, on its upper section, as shown on FIGS. 4 and 6,two transversal symmetrical wings 11 and 12 which each contain a shaft,respectively 11a and 12a, that allows the passage of an attachment screw13.

This sleeve 10 is inserted in a cylindrical housing 14 designed in thetop section 2b and is affixed to it by the attachment screws 13.

The body of the injector 1 contains, in its central section, locatedabove the bottom part 2a of the cylinder head, a peripheral groove 15 inwhich is mounted a trim 16 made of pliant metal that partially protrudesfrom the groove 15 thus forming a circular support area for the flange9.

The trim 16, shown on FIG. 5, is made of a split ring with extremities16a, 16b whose complementary shapes are designed to insure a good sealwhen they are joined.

The sleeve 10 contains, on its lower end, a circular base 17 that sitson the protruding part of the trim 16. This support base 17 contains abeveled edge 17a in order to insure a complete contact along theprotruding part of the trim and to bring the trim's extremities togetheras it exerts an axial pressure against this trim.

The exterior diameter of the sleeve 10 has a peripheral groove in whichis installed a sealing ring gasket 19.

The affixing of an injector 1 on the cylinder head 2 with the aid of theflange 9 is performed in the following manner, the two parts 2a and 2bof the cylinder head being already assembled.

During the first step, the operator inserts the body of the injector inthe bore 10a of the flange 9 then sets the trim 16 in the peripheralgroove 15.

The operator then inserts the lower section of the injector body in thehollow 4 of the bottom part 2a of the cylinder head, also inserting theflange 9 and the associated seal gasket 19 in the housing 14 of the toppart 2b.

Finally, flange 9 is attached to the top part 2b by attachment screws 13whose tightening forces the flange toward the bottom against the trim16, thus upon the injector 1 until its lower section rests on the bottom8 of the well 4. This force produces the contact and sealing of the twotrim extremities.

Please note that the wings 11 and 12 of the flange 9 are spaced from theoutside surface 20 of the top part 2b, to allows a play for the screws13 because of the different thermal dilations of the injector and of thecylinder head.

Such a device according to the invention has the advantage of reducingthe crowding in chamber 5 around the injector and to insure a good sealof chamber 5 (which contains the oil cloud), while being simple toimplement and of slight cost.

Furthermore, this implementation allows, through the sleeve of theflange, a stable support of the injector near its head 21 and thus ofits associated structures, thus reducing the common upper precariousbalance that harms the injector's reliability.

What is claimed is:
 1. A device for attaching a fuel injector to aninternal combustion engine cylinder head that consists of a bottom part(2a) designed to cover at least one engine cylinder and a top part (2b),which defines with said bottom part a chamber (5) that containsmechanical valve actuators, the injector (1) passing through said topand bottom parts and being supported at the base (8) of a well (4) ofthe bottom part (2a) by a flange (9) attached to the cylinder head withscrews (13), and by means of a tubular piece (10) that encloses the bodyof the injector and rests on the protruding section of a trim ring (16)mounted in a peripheral groove (15) in the injector body, wherein theflange (9) is rigidly integrated with the tubular piece, made of asleeve (10), which is inserted in a cylindrical hollow (14) of the toppart (2b).
 2. The attachment device according claim 1, wherein thesleeve (10) contains a bore (10a) in which is inserted the body of theinjector (1) and a peripheral groove (18) in which is mounted thesealing gasket (19).
 3. The attachment device according to claim 1,wherein the trim ring (16) is made of a split ring whose ends (16a, 16b)complement each other in order to insure a proper seal between the bodyof the injector and the bore of the sleeve when said sleeve (10) ispressed against the trim when the flange (19) is attached to the headcylinder.
 4. The attachment device according to claim 3, wherein a lowerpart of the sleeve (10) contains a circular base (17) with beveled edges(17a) designed to insure the coming together of the ends of the trimring.